Building automation systems provide the capability of managing building management components from a central interface or location. These building management components include various equipment for controlling lighting, power, heating, ventilation, air conditioning, fire safety, and security. The building automation systems provide operational and sustainability benefits to building developers, managers, and occupants. Systems may be optimized for occupant comfort and energy efficiency.
Customer requests and government regulations often specify that lighting fixtures dim to save energy when ambient light from the sun or other fixtures provide supplemental ambient lighting. Some control strategies use a single light sensor to dim an entire group of fixtures. However, a single light sensor does not reliably represent ambient readings across an entire indoor or outdoor space, resulting in light levels from light fixtures that are either too dim or too bright for occupants. Other control strategies use a light sensor at each light fixture to dim the fixtures individually. Although energy consumption and occupant comfort may be controlled for each individual fixture, consumption and comfort are not well managed for the general area illuminated by the group of light fixtures.
Designers of enclosed or partially-enclosed environments, such as business offices, desire lighting techniques that optimize for aesthetics as well as occupant comfort and energy efficiency. Lighting that is aesthetically pleasing for such environments is particularly challenging when ambient lighting includes supplemental daylight, such as sunlight entering through a window. For example, undesirable patterns of light and shade on the walls and ceilings may exist for individually managed fixtures. Also, if the lighting spread over a wide area, such as a spotlight pointed at the ceiling of a dome, existing approaches do not allow for adjustments to the light level in view of ambient light levels spread over this same area. Conventional lighting systems have limited capabilities and intelligence and, thus, do not provide optimal, aesthetically pleasing illumination for a managed area.